Elizabeth Watson was a Boston-born slave in Halifax, Nova Scotia. After a brutal assault at the hands of master-shipwright Elias Marshall, she petitioned the Halifax Inferior Court of Common Pleas. Watson won her freedom on 23 March 1778. Thirty-one days later, she was seized by Halifax butcher William Proud, who claimed Watson was his runaway slave known as Phillis. The ensuing trial is the object of this thesis, which will survey the historiography of slavery in the Maritime provinces, explore the development of slavery in New England and Nova Scotia, and provide an account of Watson v. Proud. Elizabeth Watson's story is a departure from well-known narratives of African American freedom in Canada. Its telling complicates and nuances historical analyses of the black Atlantic world. Her actions raise important questions and convey potential answers. In petitioning the lower court, she revealed a keen understanding of the legal world she inhabited and her rights as a British subject. Watson's story constitutes the earliest extant record of re-enslavement in the region. But she was also the first enslaved woman to seek possession of her freedom in a Maritime court of law. Elizabeth Watson oscillated from slavery to freedom and back to slavery in the space of thirty-one days. Tracing the genealogy of her unfreedom from Boston to Halifax brings both worlds into a fuller, more vivid light.